Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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919 FXUS65 KBOU 011125 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 525 AM MDT Sat Jun 1 2024 .KEY MESSAGES... - Afternoon showers/thunderstorms possible today, strongest from Morgan County east in the late afternoon/evening. - Still a chance of a couple severe storms Sunday over the northeast corner of the state - Summer heat through most of next week, with a few 90 degree readings over the plains. && .SHORT TERM /Through tonight/... Issued at 225 AM MDT Sat Jun 1 2024 The thermal ridge amplifies today underneath largely zonal flow, with temperatures climbing approximately 10F for the plains/urban corridor and mostly 5 degrees or less in the mountains. Meanwhile, a weak shortwave will traverse northeast Colorado. Ample instability in excess of 1,000 J/Kg should be in place across the eastern plains come the afternoon, aligning with an area of enhanced surface moisture with dewpoints into the 50`s. Those numbers will be closer to 35-40F with increased proximity to the foothills. Despite the humbling past couple of days of convective forecasts across the urban corridor, believe the notably drier conditions near the surface and more marginal instability should prevent development of any overly strong thunderstorms, instead favoring mostly high-based showers and thunderstorms for the I-25 corridor and mountains. Conditions will become progressively more favorable for deeper convection late afternoon and into the evening as storms push into the eastern plains, with the greatest potential for severe hail and winds or an isolated tornado focused generally from Morgan County eastward. && .LONG TERM /Sunday through Friday/... Issued at 225 AM MDT Sat Jun 1 2024 Sunday will see further warming, with downslope flow and lee troughing on the increase. While most areas continue to dry, low level moisture appears to hold over the northeast plains. When combined with daytime heating, MLCAPE near 1000-1500 J/kg and still sufficient shear will result in potential of a severe storm or two. Appears the main chance of that would be east of a Sterling to Akron line. With regard to the heat, Denver will have a chance of seeing it`s first 90F degree day. However, we do see enough mid and upper level moisture for convective cloudiness in the afternoon which could very well keep most highs on the plains in the upper 80s, despite the downslope. Outside of the northeast plains, it appears there is just enough moisture for virga and/or a passing light shower/weak storm, but that will spell gusty outflow winds and enhanced downslope breezes off the Front Range. Monday will feature a continuation of very warm weather with a flat ridge spreading across the Central Rockies. High temperatures should warm another degree or two with a little less convective cloud cover and the flat ridging, so many plains locations should reach 90F. We`ll still have a chance of high based late day shower/storm over the mountains and northern border area. By Monday night and Tuesday, a passing shortwave across the northern U.S. will push a "cold" front across northeast Colorado. We`ll use that term loosely, since this will be a relatively shallow push and warm temperatures remain aloft. Nonetheless, we`ll likely shave a few degrees off our highs for Tuesday. Warmer weather should then return for Wednesday with near 90, before gradual cooling (at least in the ensembles) is indicated for the end of next week. There is a fair amount of uncertainty here, and any chance of meaningful precipitation will likely hold off until at least Friday or Saturday. && .AVIATION /12Z TAFS through 12Z Sunday/... Issued at 523 AM MDT Sat Jun 1 2024 Winds will become light and variable after ~15Z Sat, with generally east/southeast flow favored later in the day with signs of DCVZ development to the SW of KDEN. However, wind direction is the most uncertain variable for Saturday and will likely be driven by thunderstorm outflows in the afternoon. Primary window for any convective activity in the vicinity of the Denver metro is 20-02Z. Dry low levels should lead to relatively high bases at/above 080-090, so leaning towards mostly isolated high-based showers/virga for I-15 corridor, with stronger storms more favored for areas to the east of KDEN. Expect return to south/southwest drainage flow Saturday evening. && .HYDROLOGY... Issued at 225 AM MDT Sat Jun 1 2024 With the arrival of summer heat, snowmelt season and runoff will really get rolling over the next few days. Hydrologic forecasts from the River Forecast Centers show a few streams getting to action stage by Monday or Tuesday, which means flows will be high and fast but flooding threat appears limited. Please use caution and respect these fast moving and cold flows in the high country. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Rodriguez LONG TERM...Barjenbruch AVIATION...Rodriguez HYDROLOGY...Barjenbruch